1999 - WAEC Chemistry Past Questions and Answers - page 1
1
Which of the following atoms contains the highest number of electrons in the outermost shell?
A
8O
B
10Ne
C
15P
D
19K
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2
What is the electronic configuration of an element represented as 199X?
A
1s 22s2 2p 5
B
1s22s23s23p3
C
1s2 2s2 2p 33s2
D
1s 22s22p 63s23p64s 1
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3
Pauli Exclusion Principle is related to
A
quantum numbers of electrons
B
reversiblility of equlibrium reactions
C
electronegativity values of elements
D
collision theory of reaction rates
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4
Which of the orbitals 4s, 4p, 4d and 4f has the lowest energy?
A
4f
B
4p
C
4d
D
4s
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5
Two radioactive elements Q and S have half-life periods of 10 hours and 20 hours respectively. Therefore
A
S decays faster than Q
B
Q is twice as stable as S
C
Q emits fewer particles than S
D
S is more stable than Q
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6
Calcium atom ionizes by
A
gaining two electrons
B
losing two electrons
C
sharing two electrons
D
gaining two protons
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7
Which of the following properties increases down a group in the Periodic Table?
A
Atomic radius
B
Electronegativity
C
Electon affinity
D
Ionization energy
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8
In the Periodic Table, the elements that loss electrons most readily belong to
A
Group 1 A
B
Group 11 A
C
Group 111 A
D
Group V11 A
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9
Which of the following reactions is not feasible?
A
Cl2 + 2Kl → 2KCI + I2
B
Cl2 + 2NaF → 2NaCI + F2
C
Zn + CuCI2 ZnCl2 + Cu
D
Zn + 2AgNO3 → Zn(NO3)2 + 2Ag
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10
Which of the following halogens is the most reactive?
A
F2
B
Br2
C
l2
D
Cl
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